com.google.gson.internal.bind.TypeAdapters Java Examples

/**
 * Configures Gson for custom serialization or deserialization. This method combines the
 * registration of an {@link TypeAdapter}, {@link InstanceCreator}, {@link JsonSerializer}, and a
 * {@link JsonDeserializer}. It is best used when a single object {@code typeAdapter} implements
 * all the required interfaces for custom serialization with Gson. If a type adapter was
 * previously registered for the specified {@code type}, it is overwritten.
 *
 * <p>This registers the type specified and no other types: you must manually register related
 * types! For example, applications registering {@code boolean.class} should also register {@code
 * Boolean.class}.
 *
 * @param type the type definition for the type adapter being registered
 * @param typeAdapter This object must implement at least one of the {@link TypeAdapter},
 * {@link InstanceCreator}, {@link JsonSerializer}, and a {@link JsonDeserializer} interfaces.
 * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
 */
@SuppressWarnings({"unchecked", "rawtypes"})
public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
  $Gson$Preconditions.checkArgument(typeAdapter instanceof JsonSerializer<?>
      || typeAdapter instanceof JsonDeserializer<?>
      || typeAdapter instanceof InstanceCreator<?>
      || typeAdapter instanceof TypeAdapter<?>);
  if (typeAdapter instanceof InstanceCreator<?>) {
    instanceCreators.put(type, (InstanceCreator) typeAdapter);
  }
  if (typeAdapter instanceof JsonSerializer<?> || typeAdapter instanceof JsonDeserializer<?>) {
    TypeToken<?> typeToken = TypeToken.get(type);
    factories.add(TreeTypeAdapter.newFactoryWithMatchRawType(typeToken, typeAdapter));
  }
  if (typeAdapter instanceof TypeAdapter<?>) {
    factories.add(TypeAdapters.newFactory(TypeToken.get(type), (TypeAdapter)typeAdapter));
  }
  return this;
}
 

private TypeAdapter<Number> doubleAdapter(boolean serializeSpecialFloatingPointValues) {
  if (serializeSpecialFloatingPointValues) {
    return TypeAdapters.DOUBLE;
  }
  return new TypeAdapter<Number>() {
    @Override public Double read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return in.nextDouble();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      double doubleValue = value.doubleValue();
      checkValidFloatingPoint(doubleValue);
      out.value(value);
    }
  };
}
 

private TypeAdapter<Number> floatAdapter(boolean serializeSpecialFloatingPointValues) {
  if (serializeSpecialFloatingPointValues) {
    return TypeAdapters.FLOAT;
  }
  return new TypeAdapter<Number>() {
    @Override public Float read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return (float) in.nextDouble();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      float floatValue = value.floatValue();
      checkValidFloatingPoint(floatValue);
      out.value(value);
    }
  };
}
 

private static TypeAdapter<Number> longAdapter(LongSerializationPolicy longSerializationPolicy) {
  if (longSerializationPolicy == LongSerializationPolicy.DEFAULT) {
    return TypeAdapters.LONG;
  }
  return new TypeAdapter<Number>() {
    @Override public Number read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return in.nextLong();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      out.value(value.toString());
    }
  };
}
 

/**
 * Configures Gson for custom serialization or deserialization. This method combines the
 * registration of an {@link TypeAdapter}, {@link InstanceCreator}, {@link JsonSerializer}, and a
 * {@link JsonDeserializer}. It is best used when a single object {@code typeAdapter} implements
 * all the required interfaces for custom serialization with Gson. If a type adapter was
 * previously registered for the specified {@code type}, it is overwritten.
 *
 * <p>This registers the type specified and no other types: you must manually register related
 * types! For example, applications registering {@code boolean.class} should also register {@code
 * Boolean.class}.
 *
 * @param type the type definition for the type adapter being registered
 * @param typeAdapter This object must implement at least one of the {@link TypeAdapter},
 * {@link InstanceCreator}, {@link JsonSerializer}, and a {@link JsonDeserializer} interfaces.
 * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
 */
@SuppressWarnings({"unchecked", "rawtypes"})
public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
  $Gson$Preconditions.checkArgument(typeAdapter instanceof JsonSerializer<?>
      || typeAdapter instanceof JsonDeserializer<?>
      || typeAdapter instanceof InstanceCreator<?>
      || typeAdapter instanceof TypeAdapter<?>);
  if (typeAdapter instanceof InstanceCreator<?>) {
    instanceCreators.put(type, (InstanceCreator) typeAdapter);
  }
  if (typeAdapter instanceof JsonSerializer<?> || typeAdapter instanceof JsonDeserializer<?>) {
    TypeToken<?> typeToken = TypeToken.get(type);
    factories.add(TreeTypeAdapter.newFactoryWithMatchRawType(typeToken, typeAdapter));
  }
  if (typeAdapter instanceof TypeAdapter<?>) {
    factories.add(TypeAdapters.newFactory(TypeToken.get(type), (TypeAdapter)typeAdapter));
  }
  return this;
}
 

@SuppressWarnings("unchecked")
private void addTypeAdaptersForDate(String datePattern, int dateStyle, int timeStyle,
    List<TypeAdapterFactory> factories) {
  DefaultDateTypeAdapter dateTypeAdapter;
  TypeAdapter<Timestamp> timestampTypeAdapter;
  TypeAdapter<java.sql.Date> javaSqlDateTypeAdapter;
  if (datePattern != null && !"".equals(datePattern.trim())) {
    dateTypeAdapter = new DefaultDateTypeAdapter(Date.class, datePattern);
    timestampTypeAdapter = (TypeAdapter) new DefaultDateTypeAdapter(Timestamp.class, datePattern);
    javaSqlDateTypeAdapter = (TypeAdapter) new DefaultDateTypeAdapter(java.sql.Date.class, datePattern);
  } else if (dateStyle != DateFormat.DEFAULT && timeStyle != DateFormat.DEFAULT) {
    dateTypeAdapter = new DefaultDateTypeAdapter(Date.class, dateStyle, timeStyle);
    timestampTypeAdapter = (TypeAdapter) new DefaultDateTypeAdapter(Timestamp.class, dateStyle, timeStyle);
    javaSqlDateTypeAdapter = (TypeAdapter) new DefaultDateTypeAdapter(java.sql.Date.class, dateStyle, timeStyle);
  } else {
    return;
  }

  factories.add(TypeAdapters.newFactory(Date.class, dateTypeAdapter));
  factories.add(TypeAdapters.newFactory(Timestamp.class, timestampTypeAdapter));
  factories.add(TypeAdapters.newFactory(java.sql.Date.class, javaSqlDateTypeAdapter));
}
 

private TypeAdapter<Number> doubleAdapter(boolean serializeSpecialFloatingPointValues) {
  if (serializeSpecialFloatingPointValues) {
    return TypeAdapters.DOUBLE;
  }
  return new TypeAdapter<Number>() {
    @Override public Double read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return in.nextDouble();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      double doubleValue = value.doubleValue();
      checkValidFloatingPoint(doubleValue);
      out.value(value);
    }
  };
}
 

private TypeAdapter<Number> floatAdapter(boolean serializeSpecialFloatingPointValues) {
  if (serializeSpecialFloatingPointValues) {
    return TypeAdapters.FLOAT;
  }
  return new TypeAdapter<Number>() {
    @Override public Float read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return (float) in.nextDouble();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      float floatValue = value.floatValue();
      checkValidFloatingPoint(floatValue);
      out.value(value);
    }
  };
}
 

private TypeAdapter<Number> longAdapter(LongSerializationPolicy longSerializationPolicy) {
  if (longSerializationPolicy == LongSerializationPolicy.DEFAULT) {
    return TypeAdapters.LONG;
  }
  return new TypeAdapter<Number>() {
    @Override public Number read(JsonReader in) throws IOException {
      if (in.peek() == JsonToken.NULL) {
        in.nextNull();
        return null;
      }
      return in.nextLong();
    }
    @Override public void write(JsonWriter out, Number value) throws IOException {
      if (value == null) {
        out.nullValue();
        return;
      }
      out.value(value.toString());
    }
  };
}
 

public static JsonElement parse(JsonReader reader) throws JsonParseException {
    boolean isEmpty = true;
    try {
        reader.peek();
        isEmpty = false;
        return (JsonElement) TypeAdapters.JSON_ELEMENT.read(reader);
    } catch (Throwable e) {
        if (isEmpty) {
            return JsonNull.INSTANCE;
        }
        throw new JsonIOException(e);
    } catch (Throwable e2) {
        throw new JsonSyntaxException(e2);
    } catch (Throwable e22) {
        throw new JsonIOException(e22);
    } catch (Throwable e222) {
        throw new JsonSyntaxException(e222);
    }
}
 

public GsonBuilder registerTypeHierarchyAdapter(Class<?> baseType, Object typeAdapter) {
    boolean z;
    if ((typeAdapter instanceof JsonSerializer) || (typeAdapter instanceof JsonDeserializer) || (typeAdapter instanceof TypeAdapter)) {
        z = true;
    } else {
        z = false;
    }
    C$Gson$Preconditions.checkArgument(z);
    if ((typeAdapter instanceof JsonDeserializer) || (typeAdapter instanceof JsonSerializer)) {
        this.hierarchyFactories.add(0, TreeTypeAdapter.newTypeHierarchyFactory(baseType, typeAdapter));
    }
    if (typeAdapter instanceof TypeAdapter) {
        this.factories.add(TypeAdapters.newTypeHierarchyFactory(baseType, (TypeAdapter) typeAdapter));
    }
    return this;
}
 

public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
    boolean z = (typeAdapter instanceof JsonSerializer) || (typeAdapter instanceof JsonDeserializer) || (typeAdapter instanceof InstanceCreator) || (typeAdapter instanceof TypeAdapter);
    C$Gson$Preconditions.checkArgument(z);
    if (Primitives.isPrimitive(type) || Primitives.isWrapperType(type)) {
        throw new IllegalArgumentException("Cannot register type adapters for " + type);
    }
    if (typeAdapter instanceof InstanceCreator) {
        this.instanceCreators.put(type, (InstanceCreator) typeAdapter);
    }
    if ((typeAdapter instanceof JsonSerializer) || (typeAdapter instanceof JsonDeserializer)) {
        this.factories.add(TreeTypeAdapter.newFactoryWithMatchRawType(TypeToken.get(type), typeAdapter));
    }
    if (typeAdapter instanceof TypeAdapter) {
        this.factories.add(TypeAdapters.newFactory(TypeToken.get(type), (TypeAdapter) typeAdapter));
    }
    return this;
}
 

private TypeAdapter<Number> longAdapter(LongSerializationPolicy longSerializationPolicy) {
    if (longSerializationPolicy == LongSerializationPolicy.DEFAULT) {
        return TypeAdapters.LONG;
    }
    return new TypeAdapter<Number>() {
        public Number read(JsonReader in) throws IOException {
            if (in.peek() != JsonToken.NULL) {
                return Long.valueOf(in.nextLong());
            }
            in.nextNull();
            return null;
        }

        public void write(JsonWriter out, Number value) throws IOException {
            if (value == null) {
                out.nullValue();
            } else {
                out.value(value.toString());
            }
        }
    };
}
 

private TypeAdapter<Number> floatAdapter(boolean serializeSpecialFloatingPointValues) {
    if (serializeSpecialFloatingPointValues) {
        return TypeAdapters.FLOAT;
    }
    return new TypeAdapter<Number>() {
        public Float read(JsonReader in) throws IOException {
            if (in.peek() != JsonToken.NULL) {
                return Float.valueOf((float) in.nextDouble());
            }
            in.nextNull();
            return null;
        }

        public void write(JsonWriter out, Number value) throws IOException {
            if (value == null) {
                out.nullValue();
                return;
            }
            Gson.this.checkValidFloatingPoint((double) value.floatValue());
            out.value(value);
        }
    };
}
 

private TypeAdapter<Number> doubleAdapter(boolean serializeSpecialFloatingPointValues) {
    if (serializeSpecialFloatingPointValues) {
        return TypeAdapters.DOUBLE;
    }
    return new TypeAdapter<Number>() {
        public Double read(JsonReader in) throws IOException {
            if (in.peek() != JsonToken.NULL) {
                return Double.valueOf(in.nextDouble());
            }
            in.nextNull();
            return null;
        }

        public void write(JsonWriter out, Number value) throws IOException {
            if (value == null) {
                out.nullValue();
                return;
            }
            Gson.this.checkValidFloatingPoint(value.doubleValue());
            out.value(value);
        }
    };
}
 

/**
 * Configures Gson for custom serialization or deserialization for an inheritance type hierarchy.
 * This method combines the registration of a {@link TypeAdapter}, {@link JsonSerializer} and
 * a {@link JsonDeserializer}. If a type adapter was previously registered for the specified
 * type hierarchy, it is overridden. If a type adapter is registered for a specific type in
 * the type hierarchy, it will be invoked instead of the one registered for the type hierarchy.
 *
 * @param baseType the class definition for the type adapter being registered for the base class
 *        or interface
 * @param typeAdapter This object must implement at least one of {@link TypeAdapter},
 *        {@link JsonSerializer} or {@link JsonDeserializer} interfaces.
 * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
 * @since 1.7
 */
@SuppressWarnings({"unchecked", "rawtypes"})
public GsonBuilder registerTypeHierarchyAdapter(Class<?> baseType, Object typeAdapter) {
  $Gson$Preconditions.checkArgument(typeAdapter instanceof JsonSerializer<?>
      || typeAdapter instanceof JsonDeserializer<?>
      || typeAdapter instanceof TypeAdapter<?>);
  if (typeAdapter instanceof JsonDeserializer || typeAdapter instanceof JsonSerializer) {
    hierarchyFactories.add(0,
        TreeTypeAdapter.newTypeHierarchyFactory(baseType, typeAdapter));
  }
  if (typeAdapter instanceof TypeAdapter<?>) {
    factories.add(TypeAdapters.newTypeHierarchyFactory(baseType, (TypeAdapter)typeAdapter));
  }
  return this;
}
 

private <A> TypeAdapter<Optional<A>> optionalAdapter(TypeAdapter<A> innerAdapter) {
    return new TypeAdapter<Optional<A>>() {
        @Override
        public Optional<A> read(JsonReader in) throws IOException {
            if (in.peek() == JsonToken.NULL) {
                in.nextNull();
                return Optional.empty();
            }
            else {
                JsonElement json = TypeAdapters.JSON_ELEMENT.read(in);
                try {
                    A value = innerAdapter.fromJsonTree(json);
                    return Optional.of(value);
                }
                catch (JsonSyntaxException e) {
                    /**
                     * Note : This is a workaround and it only exists because salt doesn't differentiate between a
                     * non-existent grain and a grain which exists but has value set to empty String.
                     *
                     * If an object is expected but instead empty string comes in then we return empty Optional.
                     */
                    if (json.isJsonPrimitive() && json.getAsJsonPrimitive().isString() &&
                            json.getAsString().isEmpty()) {
                        return Optional.empty();
                    }
                    throw e;
                }
            }
        }

        @Override
        public void write(JsonWriter out, Optional<A> optional) throws IOException {
            innerAdapter.write(out, optional.orElse(null));
        }
    };
}
 

/**
 * Reading from BSON to GSON
 */
@Test
public void bsonToGson() throws Exception {
  BsonDocument document = new BsonDocument();
  document.append("boolean", new BsonBoolean(true));
  document.append("int32", new BsonInt32(32));
  document.append("int64", new BsonInt64(64));
  document.append("double", new BsonDouble(42.42D));
  document.append("string", new BsonString("foo"));
  document.append("null", new BsonNull());
  document.append("array", new BsonArray());
  document.append("object", new BsonDocument());

  JsonElement element = TypeAdapters.JSON_ELEMENT.read(new BsonReader(new BsonDocumentReader(document)));
  check(element.isJsonObject());

  check(element.getAsJsonObject().get("boolean").getAsJsonPrimitive().isBoolean());
  check(element.getAsJsonObject().get("boolean").getAsJsonPrimitive().getAsBoolean());

  check(element.getAsJsonObject().get("int32").getAsJsonPrimitive().isNumber());
  check(element.getAsJsonObject().get("int32").getAsJsonPrimitive().getAsNumber().intValue()).is(32);

  check(element.getAsJsonObject().get("int64").getAsJsonPrimitive().isNumber());
  check(element.getAsJsonObject().get("int64").getAsJsonPrimitive().getAsNumber().longValue()).is(64L);

  check(element.getAsJsonObject().get("double").getAsJsonPrimitive().isNumber());
  check(element.getAsJsonObject().get("double").getAsJsonPrimitive().getAsNumber().doubleValue()).is(42.42D);

  check(element.getAsJsonObject().get("string").getAsJsonPrimitive().isString());
  check(element.getAsJsonObject().get("string").getAsJsonPrimitive().getAsString()).is("foo");

  check(element.getAsJsonObject().get("null").isJsonNull());
  check(element.getAsJsonObject().get("array").isJsonArray());
  check(element.getAsJsonObject().get("object").isJsonObject());
}
 

private <A> TypeAdapter<Optional<A>> optionalAdapter(TypeAdapter<A> innerAdapter) {
    return new TypeAdapter<Optional<A>>() {
        @Override
        public Optional<A> read(JsonReader in) throws IOException {
            if (in.peek() == JsonToken.NULL) {
                in.nextNull();
                return Optional.empty();
            } else {
                JsonElement json = TypeAdapters.JSON_ELEMENT.read(in);
                try {
                    A value = innerAdapter.fromJsonTree(json);
                    return Optional.of(value);
                }
                catch (JsonSyntaxException e) {
                    /**
                     * Note : This is a workaround and it only exists because salt doesn't differentiate between a
                     * non-existent grain and a grain which exists but has value set to empty String.
                     *
                     * If an object is expected but instead empty string comes in then we return empty Optional.
                     */
                    if (json.isJsonPrimitive() && json.getAsJsonPrimitive().isString() &&
                            json.getAsString().isEmpty()) {
                        return Optional.empty();
                    }
                    throw e;
                }
            }
        }

        @Override
        public void write(JsonWriter out, Optional<A> optional) throws IOException {
            innerAdapter.write(out, optional.orElse(null));
        }
    };
}
 

/**
 * Tests direct bson and gson mappings
 */
@Test
public void gsonToBson() throws Exception {
  JsonObject obj = new JsonObject();
  obj.addProperty("boolean", true);
  obj.addProperty("int32", 32);
  obj.addProperty("int64", 64L);
  obj.addProperty("double", 42.42D);
  obj.addProperty("string", "foo");
  obj.add("null", JsonNull.INSTANCE);
  obj.add("array", new JsonArray());
  obj.add("object", new JsonObject());


  BsonDocument doc = Jsons.toBson(obj);
  TypeAdapters.JSON_ELEMENT.write(new BsonWriter(new BsonDocumentWriter(doc)), obj);

  check(doc.keySet()).notEmpty();

  check(doc.get("boolean").getBsonType()).is(BsonType.BOOLEAN);
  check(doc.get("boolean").asBoolean());
  check(doc.get("int32").getBsonType()).is(BsonType.INT32);
  check(doc.get("int32").asInt32().getValue()).is(32);
  check(doc.get("int64").getBsonType()).is(BsonType.INT64);
  check(doc.get("int64").asInt64().getValue()).is(64L);
  check(doc.get("double").getBsonType()).is(BsonType.DOUBLE);
  check(doc.get("double").asDouble().getValue()).is(42.42D);
  check(doc.get("string").getBsonType()).is(BsonType.STRING);
  check(doc.get("string").asString().getValue()).is("foo");
  check(doc.get("null").getBsonType()).is(BsonType.NULL);
  check(doc.get("null").isNull());
  check(doc.get("array").getBsonType()).is(BsonType.ARRAY);
  check(doc.get("array").asArray()).isEmpty();
  check(doc.get("object").getBsonType()).is(BsonType.DOCUMENT);
  check(doc.get("object").asDocument().keySet()).isEmpty();
}
 

private TypeAdapter b(boolean flag)
{
    if (flag)
    {
        return TypeAdapters.FLOAT;
    } else
    {
        return new j(this);
    }
}
 

private TypeAdapter a(boolean flag)
{
    if (flag)
    {
        return TypeAdapters.DOUBLE;
    } else
    {
        return new i(this);
    }
}
 

private TypeAdapter a(LongSerializationPolicy longserializationpolicy)
{
    if (longserializationpolicy == LongSerializationPolicy.DEFAULT)
    {
        return TypeAdapters.LONG;
    } else
    {
        return new k(this);
    }
}
 

@Before
public void onTestBefore() {
    mGson = new GsonBuilder()
            .registerTypeAdapterFactory(TypeAdapters.newFactory(String.class, new StringTypeAdapter()))
            .registerTypeAdapterFactory(TypeAdapters.newFactory(boolean.class, Boolean.class, new BooleanTypeAdapter()))
            .registerTypeAdapterFactory(TypeAdapters.newFactory(int.class, Integer.class, new IntegerTypeAdapter()))
            .registerTypeAdapterFactory(TypeAdapters.newFactory(long.class, Long.class, new LongTypeAdapter()))
            .registerTypeAdapterFactory(TypeAdapters.newFactory(float.class, Float.class, new FloatTypeAdapter()))
            .registerTypeAdapterFactory(TypeAdapters.newFactory(double.class, Double.class, new DoubleTypeAdapter()))
            .registerTypeHierarchyAdapter(List.class, new ListTypeAdapter())
            .create();
}
 

default TypeAdapterFactory createBooleanTypeAdapterFactory() {
    return TypeAdapters.newFactory(boolean.class, Boolean.class, createTypeAdapterBoolean());
}
 

JsonReaderSupplier(JsonReader in) throws IOException {
  this.element = TypeAdapters.JSON_ELEMENT.read(in);
}
 

static JsonObject toGson(BsonDocument bson) throws IOException {
  return TypeAdapters.JSON_ELEMENT.read(asGsonReader(bson)).getAsJsonObject();
}
 

static org.bson.BsonReader asBsonReader(JsonObject gson) throws IOException {
  BasicOutputBuffer buffer = new BasicOutputBuffer();
  BsonWriter writer = new BsonWriter(new BsonBinaryWriter(buffer));
  TypeAdapters.JSON_ELEMENT.write(writer, gson);
  return new BsonBinaryReader(ByteBuffer.wrap(buffer.toByteArray()));
}
 

private static void compare(String string) throws IOException {
  JsonElement bson = TypeAdapters.JSON_ELEMENT.read(new BsonReader(new JsonReader(string))); // compare as BSON
  JsonElement gson = TypeAdapters.JSON_ELEMENT.fromJson(string); // compare as JSON
  check(bson).is(gson); // compare the two
}
 

public static void write(JsonElement element, JsonWriter writer) throws IOException {
    TypeAdapters.JSON_ELEMENT.write(writer, element);
}